Electric fuse



Feb. 6, 1934. K, T 1,945,540

' ELECTRI C FUSE Original Filed Oct. 1, 1930 BEDFORD K. JM/TH- Serial No. 485,731, filed October 1, 1930, entitled Patented Feb. 6, 1934 ELECTRIC FUSE Bedford K. Smith, Alexandria, Va.

Original application October 1, 1930, Serial No. 485,731. Divided and this application March 1, 1933. Serial No. 659,155

3 Claims. 01. 2o0 130 (Granted under the act of March 8, 1883, as

amended April 30, 1928; 370 O. G. 757) My invention relates broadly to protective electric fuses and more particularly to a renewable fuse for the protection of electric circuits. I

This application is a division of my application Electric fuse.

One of the objects of my invention is to provide a simplified construction of renewable fuse the protecting electric circuits which is inexpen: sive in manufacture and production and'which may be refilled within minimum time without a large degree of .skill.

Another object of my invention is to provide a construction of renewable electric fuse wherein the parts which house the fuse may be displaced one relative to another for receiving a renewal fuse and thereafter closed upon each other for housing the renewal fuse.

7 Still another object of my invention is to provide a simplified construction of renewable fuse having an insulated housing with parts arranged to slide longitudinally one with respect to another for housing a renewal fuse and establish electrical connection with opposite ends thereof.

A further object of my invention is to provide a construction of renewable fuse in which parts of the fuse may be assembled or disassembled by hand without the employment of tools.

A still further object of my invention is to provide a construction of screw plug fuse adapted to fit standard screw sockets and in which the parts of the fuse are longitudinally separable for readily replacing a fuse after the fuse has been blown.

Other and further objects of my invention reside in the design of a renewable fuse set forth in the specification hereinafter following by reference to the accompanying drawing, in which:

Figure 1 is a cross-sectional View illustrating the renewable fuse of my invention wherein a screw plug member may be screwed into a receptacle for the connection of the fuse in a protective circuit; and Fig. 2 is a cross sectional view of the fuse shown in Fig. 1 taken on line 2'-2 of Fig. 1.

My invention is directed to a simplified construction of renewable fuse plug capable of economic manufacture on a quantity production basis and adapted to be readily refilled after rupture of the fuse. I have had considerable experience with many different types of renewable fuse plugs. Heretofore manufacturers in endeavoring to produce a renewable fuse plug have rendered the construction thereof so elaborate that the filling and refilling operation requires the use of tools and the expenditure of a substantial time interval. In my construction of renewable fuse plug, the parts are reduced to a mini mum and the construction thereof so simplified that a renewal operation may be effected without employing tools. The renewal operation'in the construction of fuse plug of my invention requires only a brief interval of time for an operation which may be performed by a simple sliding movement.

Referring to'the drawing in detail, the fuse plug of my invention constitutes a screw base 24 provided on an insulating end portion 20 which extends integral with the cylindrical insulating portion shown at 19. A central contact 21 in insulating base 20 connects to a contact plate 22 extending in alignment with the face of the channelway 27 of upwardly projecting portion 19. The screw portion 24 is connected through conductor 23 to a plate member 23a on the face of the channelway 2'7 in the insulating portion 19. A semi-circular insulating portion 18 constructed for cooperative alignment with the insulating portion 19 carries a pair of brush members indicated at 18a and 18b aligned with plate member 22 and conductive member 23a in the channelway 27 across which the renewable fuse 25 connects. The brushes 18a and 18b serve to press the ends of the fuse 25 into electrical connection with the conductive plate 22 and the conductive plate 23a thereby maintaining the fuse in an electrical circuit between the center plug 21 and the screw base 24. I provide cooperatively aligned grooves and projections in the parts 18 and 19 for insuring a substantially gas tight shell for the fuse. The insulating portion 18 of the renewable fuse is provided with end cap 26 connected thereto by means of pin 26a. By grasping the end cap 26, the insulating portion 18 may be longitudinally withdrawn from the socket portion 20 exposing the channelway 2'7 and enabling a renewal fuse 25 to be disposed therein and the fuse cartridge thereafter closed. The port 26b in the end cap 26 is aligned with the channelway 2'7 enabling the discharge of destructive pressures or gases without injury to the parts of the fuse cartridge proper.

The fuse plug of my invention may be readily inserted in the standard socket receptacle. The disassembly of the fuse to remove a burned out fuse and insert a new fuse may be accomplished rapidly.

The device of my invention is inexpensive in its production and assembly and thereby decreases the cost of fuses used in domestic and other installations. While I have described my invention in certain preferred embodiments, I desire that it be understood that modifications may be made and that no limitations upon my invention are intended other than those imposed by the scope of the appended claims.

The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalty thereon or therefor.

What I claim as new and desire to secure by Letters Patent of the United States is as follows:

1. An electric fuse comprising an insulated casing constituted by a pair of coacting separable parts displaceable in position one with respect to another, a screw plug forming electrical terminals carried on the end of one of said separable parts, an end cap carried by the opposite separable part and adapted to envelop the opposite ends of said separable parts when in assembled position, a channelway defined by the separable parts when in aligned position, a renewable fuse extending through said channelway, and means for establishing connection between the opposite ends of said fuse and the terminals of said screw plug.

2. An electric fuse comprising a pair of separable casings, guide means for aligning said casings one with another, a longitudinally extending ohannelway defined by said separable casings, a two terminal screw plug carried by one end of one of said separable casings and having a socket therein for receiving the end of the other of said separable casings and a cap embracing the opposite ends of said separable casings for maintaining said seperable casings in position, a fusible element extending through said channelway, means carried by said separable casings for completing connections between the ends of said fusible element and the terminals of said screw plug, and means carried by said last mentioned separable section for maintaining said fusible element in electrical connection with said aforesaid means.

3. An electric fuse comprising a pair of insu lating separable sections having coacting peripheral joints for aligning said sections one with the other, a screw plug including a pair of terminals carried by the end of one of said separable sections, an end cap adapted to engage opposite ends of said separable sections for securing said sections in position, a channelway extending 1ongitudinally through said sections and adapted to receive a renewable fuse element therebetween, and means on the interior faces of said insulating separable sections for completing connection between the ends of said fusible element and a pair of terminals on said screw plug.

BEDFORD K. SMITH. 

